Titers of FVIII-binding antibodies assessed for individual Ig isotypes and IgG subclasses. The detected titers of Ig isotypes and IgG subclasses of FVIII-binding antibodies for (A) healthy individuals, (B) hemophilia A patients without inhibitors (HA-noINH), (C) hemophilia A patients with inhibitors (HA-INH), (D) acquired hemophilia A (Acqu-HA) patients, and (E) hemophilia A patients after successful ITI (HA-ITI) are shown. Plasma samples were diluted at least 1:20. Samples that did not give a positive signal at this minimum dilution were considered as negative (not detectable [ND]). The dotted line at a titer of 1:80 indicates the minimum titer required for proof of specificity. Titers of < 1:80 were too low to be confirmed for specificity.